Nicotinate-adenine dinucleotide phosphate-induced Ca2+ release does not behave as a Ca2+-induced Ca2+-release system

Eduardo N. Chini, Thomas P. Dousa

Research output: Contribution to journalArticlepeer-review

91 Scopus citations


We investigated the dependence of nicotinate-adenine dinucleotide phosphate (NAADP)-induced Ca2t release from intracellular stores of sea urchin egg homogenates, upon extravesicular Ca2+. In contrast to the Ca2+ release induced by inositol 1′,4′,5′-trisphosphate (IP3) or cyclic ADP-ribose (cADPR), the Ca2+ release induced by NAADP was completely independent of the free extravesicular Ca2+ over a wide range of concentrations (0-0.1 mM). The Ca2+ release triggered by either cADPR or IP3 was biphasically modulated by extravesicular Ca2+, and the Ca2+ release by these agents was abolished when the extravesicular Ca2+ was removed by chelation with 2 mM EGTA. On the other hand, NAADP-triggered Ca2+ release was not influenced by EGTA. These data indicate that while both cADPR and IP3 systems behave as functional Ca2+-induced Ca2+ release mechanisms, NAADP activates a Ca2+ release mechanism which is independent of the presence of extravesicular Ca2+. Therefore, the NAADP-sensitive Ca2+ release mechanisms may have a unique regulatory impact upon intracellular Ca2+ homoeostasis.

Original languageEnglish (US)
Pages (from-to)709-711
Number of pages3
JournalBiochemical Journal
Issue number3
StatePublished - Jun 15 1996

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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